The carbs are Mikuni-Solex N40PHH ( probably type 41/42 or 89/90 ). Lots of data out there if you search using the 'N40PHH' type name.

There's nothing "usual" about timing chain rattle. If its flapping about that much, there's a problem. I think you should take the front cover off and investigate further before something fails. It could be due to a stretched chain, a failing - or partially stuck - tensioner, worn chain guides, or an overskimmed cylinder head ( or any combination of the above ). Catch it quick before that chain jumps and you whack some valves.....

Those triangular box sections at the upper corners of the engine bay tend to rot from the inside out, since water from the cowl drains through them (and dumps behind the splash panel in the wheel wells). But those look pretty good, normally they go at the flanges first.

Those triangular box sections at the upper corners of the engine bay tend to rot from the inside out, since water from the cowl drains through them (and dumps behind the splash panel in the wheel wells). But those look pretty good, normally they go at the flanges first.

That's a Sanyo Kiki inlet manifold. In fact, the manifold, carbs, linkages and the triple round air filters are a complete Sanyo Sports Kit from the early to mid Seventies period.

Sanyo Kiki became more well known for using the 'SK' brand a little later....

The solid teflon bushing in the above photo has popped out of its housing on the upright. It should be secured with an 'E' clip ( which might have popped off? ) and the linkage will not be working as well as it should. Just slide it back in and see if you can stop it from coming out again. You might notice an improvement in carb balance once that's sorted.

That's a Sanyo Kiki inlet manifold. In fact, the manifold, carbs, linkages and the triple round air filters are a complete Sanyo Sports Kit from the early to mid Seventies period.

Sanyo Kiki became more well known for using the 'SK' brand a little later....

The solid teflon bushing in the above photo has popped out of its housing on the upright. It should be secured with an 'E' clip ( which might have popped off? ) and the linkage will not be working as well as it should. Just slide it back in and see if you can stop it from coming out again. You might notice an improvement in carb balance once that's sorted.